import { on, off } from "@theme/utils/dom";
import { renderThumbStyle, BAR_MAP } from "./util";

export default {
  name: "Bar",

  props: {
    vertical: Boolean,
    size: String,
    move: Number
  },

  computed: {
    bar() {
      return BAR_MAP[this.vertical ? "vertical" : "horizontal"];
    },

    wrap() {
      return this.$parent.wrap;
    }
  },

  render(h) {
    const { size, move, bar } = this;

    return (
      <div
        class={["yur-scrollbar__bar", "is-" + bar.key]}
        onMousedown={this.clickTrackHandler}
      >
        <div
          ref="thumb"
          class="yur-scrollbar__thumb"
          onMousedown={this.clickThumbHandler}
          style={renderThumbStyle({ size, move, bar })}
        />
      </div>
    );
  },

  methods: {
    clickThumbHandler(e) {
      if (e.ctrlKey || e.button === 2) {
        return;
      }
      this.startDrag(e);
      this[this.bar.axis] =
        e.currentTarget[this.bar.offset] -
        (e[this.bar.client] -
          e.currentTarget.getBoundingClientRect()[this.bar.direction]);
    },

    clickTrackHandler(e) {
      const offset = Math.abs(
        e.target.getBoundingClientRect()[this.bar.direction] -
          e[this.bar.client]
      );
      const thumbHalf = this.$refs.thumb[this.bar.offset] / 2;
      const thumbPositionPercentage =
        ((offset - thumbHalf) * 100) / this.$el[this.bar.offset];

      this.wrap[this.bar.scroll] =
        (thumbPositionPercentage * this.wrap[this.bar.scrollSize]) / 100;
    },

    startDrag(e) {
      e.stopImmediatePropagation();
      this.cursorDown = true;

      on(document, "mousemove", this.mouseMoveDocumentHandler);
      on(document, "mouseup", this.mouseUpDocumentHandler);
      document.onselectstart = () => false;
    },

    mouseMoveDocumentHandler(e) {
      if (this.cursorDown === false) return;
      const prevPage = this[this.bar.axis];

      if (!prevPage) return;

      const offset =
        (this.$el.getBoundingClientRect()[this.bar.direction] -
          e[this.bar.client]) *
        -1;
      const thumbClickPosition = this.$refs.thumb[this.bar.offset] - prevPage;
      const thumbPositionPercentage =
        ((offset - thumbClickPosition) * 100) / this.$el[this.bar.offset];

      this.wrap[this.bar.scroll] =
        (thumbPositionPercentage * this.wrap[this.bar.scrollSize]) / 100;
    },

    mouseUpDocumentHandler(e) {
      this.cursorDown = false;
      this[this.bar.axis] = 0;
      off(document, "mousemove", this.mouseMoveDocumentHandler);
      document.onselectstart = null;
    }
  },

  destroyed() {
    off(document, "mouseup", this.mouseUpDocumentHandler);
  }
};
